A number of mammalian glucose (hexose) transporters (GLUTs) have been identified. High affinity GLUTs are found in nearly every tissue. A low affinity GLUT (GLUT-2) is expressed in tissues which are associated with high glucose flux (e.g., intestine, kidney, and liver). It is thought that the level of expression of high affinity GLUTs influences the rate of glucose uptake. It is also thought that the expression of various GLUTs is regulated by glucose and various hormones (Thorens, Am. J. Physiol. 270 (Gastrointest. Liver Physiol. 33:G541-G553, 1996). Human GLUT-1 is described by Mucckler et al. (Science 229:941, 1985). Human GLUT-2 is described by Fukumoto et al. (Proc. Nat'l Acad. Sci. USA 264:776, 1989). Human GLUT-3 is described by Keller et al. (J. Biol. Chem. 264:18884, 1989). Human GLUT-4 is described by Fukumoto et al. (J. Biol. Chem. 264:7776, 1989). Human GLUT-5 is described by Kayano et al. (Nature 377:151, 1995).